Indian J. Fish., 56(3) : 215-218, 2009 215

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Age, growth and harvestable size of Cirrhinus mrigala from the Jawahar Sagar Dam, Rajasthan,

N. SARANG, L. L. SHARMA AND V. P. SAINI Department of Aquaculture, College of Fisheries,Maharana Pratap University of Agriculture and Technology, Udaipur-313 001, Rajasthan, India e-mail: [email protected]

ABSTRACT Age, growth and harvestable size of Cirrhinus mrigala from Jawahar Sagar Dam, Rajasthan, were determined using the key scales. Maximum three annual rings were found and used to assess various growth characteristics. These growth parameters indicated higher value of index of population weight growth intensity (QCW =7.43 g) and index of species average size (Qh =15.83 cm). The calculated weight of fish (Wg) was found to increase upto the third year of life. On the basis of growth parameters studied, a harvestable size of 66 cm has been assigned for Cirrhinus mrigala from the Jawahar Sagar Dam. Keywords: Age, Cirrhinus mrigala, Growth, Harvestable size

Determination of age, growth and harvestable size of was performed using a scale reader. The primary, secondary fish bears importance in management of sustainable fishery and tertiary radii of scales were examined. The method in the capture fisheries. From this point of view, study of suggested by Le Cren (1951) was followed for the body scale of fish are undoubtedly useful tools. This is well estimation of correlation between different parameters of evident from the studies conducted on many fish species. fish scale. For back calculation, the following formula was Menon (1953) worked on the age and growth of used. fimbriatus from Mettur reservoir in south India by examining scales. Johal and Tandon (1985, 1987) studied Sn (L–a) the scales in Labeo rohita. Natarajan and Jhingran (1963), Ln = a + ------(1) Kamal (1969), Rao (1974) and Pathani (1981) conducted S their studies mainly for back calculation of lengths. In the present investigation, an attempt was made to ascertain the where, role of the key scales of Cirrhinus mrigala for finding L = Length of fish when the annulus ‘n’ was formed information regarding size, scale rings and related n dimensions for calculating length at the time of annulus L = Length of fish when scale sample was obtained formation. S = Radius of annulus ‘n’ The Jawahar Sagar Dam is the third dam in the series n of Chambal Valley projects, located 29 km upstream of S = Total scale radius Kota Barrage and 26 km downstream of Rana Pratap Sagar a = Correction factor (intersecting point between TL dam, across the river Chambal. The total catchment area of and scale radius) the dam is 27,195 km2, of which only 1.496 km2 area is in Rajasthan. The Jawahar Sagar dam is used for domestic The following growth parameters were calculated and public water supply, irrigation and hydroelectric power (Johal and Tandon, 1985). generation. Further details of this dam pertaining to its morphometric features are presented in Table 1. Log Ln - Log Ln -1 Growth characteristics (Cth) =______x L (2) The key scales were obtained from selected specimens n -1 0.4343 of C. mrigala of size range 30.0 to 70.0 cm. The scales were collected randomly during November 2004 to Log Ln - Log Ln - 1 t2 + t1 November 2005. The collected scales were secured in hard Growth constant (Clt) = ______x ______(3) paper envelops for further use. The laboratory study on scale 0.4343 2 N. Sarang et al. 216

Table 1. Morphometric features of Jawahar Sagar Dam, Ln - Ln - 1 Specific rate of linear growth (CI) = ______x 100 (4) Rajasthan Location: Ln - 1 Latitude 24° 82.792N W - W n n - 1 Longitude 76° 52.072E ______Specific rate of growth increase (CW) = x 100 (5) Catchment area 10,500 m2 Wn – 1 Average rainfall (inches) 32 Index of population weight growth intensity (QCW) Maximum depth (m) 11.0 Mean depth (m) 8.0

CW = 1 Length of the dam (m) 393.0 QCW =______(6) Height of the dam (m) 45.0 nj + a Nature of the dam Cement concrete Year of impoundment 1960-1962 h – 1 ∑ nj + a Purpose Hydel power generation ______Index of species average size (Qh) = (7) Power units in MW 3 units of 33 MW nj + a Village / Town / City Jawahar Nagar where, District Bundi district

Ln, Ln-1 = Total length of fish in cm at ultimate and penultimate ages

Wn, Wn-1 = Weight of fish in g at ultimate and penultimate ages j = juvenile; a = adult, h = absolute increase in length

t1 and t2 = time intervals between ultimate and penultimate age classes The scales of Cirrhinus mrigala are of cycloid type. The regression analysis gave an “r” value of 0.902 between scale radius and fish length, while the “r” value between scale radius and fish weight was 0.676. Further, the studies of growth rings or annulii in the scale of C. mrigala showed a maximum of three rings (Fig. 1). Johal and Tandon (1987) observed spawning marks on the scale and considered it valid for age determination. According to them, factors like spawning stress, high temperature and scarcity of food are responsible for the formation of annuli. On the basis of scale studies and back calculations for lengths (Table 2), the back calculated length (L) in cm, length increment (h) in cm, annual increase in weight (W) in g, index of species Fig. 1. Image of Cirrhinus mrigala scale (3+ year class) from average size (Qh), index of population weight growth Jawahar Sagar Dam (I, II & III are annual rings)

Table 2. Back calculation for length (cm) of Cirrhinus mrigala from Jawahar Sagar Dam during November 2004 to November 2005

Age No. of Total length L1 L2 L3 L4 Group specimens at the time of capture 1+ 15.0 28.20-30.10 28.20-30.10 — — — (29.20) (29.05) 2+ 35.0 21.66-41.90 21.66-31.90 20.90-41.90 — — (29.76) (24.48) (35.05) 3+ 15.0 23.03-69.10 23.03-51.30 28.50-61.20 36.80-69.10 — (41.28) (31.44) (41.92) (47.50) Total No. = 65 Min. 24.29 24.29 29.70 36.80 — Max. 47.03 37.76 51.55 69.10 Mean 33.08 28.32 38.48 47.50 Age, growth and harvestable size of Cirrhinus mrigala 217 intensity (QCW), specific rate of linear growth (CI), specific (Table 2), the minimum harvestable size for C. mrigala rate of weight increase (CW), growth constant (Clt) and has been calculated as 66.0 cm (Fig. 2). Khan and Jhingran growth characteristic (Cth) were calculated for C. mrigala (1975) estimated the harvestable size for rohu and mrigal of Jawahar Sagar Dam and depicted in Table 3. The at their length at first maturity in the second year of life. calculated weight of fish (Wg) has shown an increasing The harvestable size calculated in the present study trend upto 3rd year of life. Balon (1968) considered the (66.0 cm) appears satisfactory and would offer fair chance average values of growth characteristic (Cth) as a useful for the fish to spawn before it is caught. Interestingly, the

Table 3. Growth characteristics of Cirrhinus mrigala based on back calculations, during 2004-05 from Jawahar Sagar Dam Parameters Year of life 123 L (cm) 28.32 38.48 47.50 h 28.32 10.16 9.02 Qh 15.83 Cl 35.87 23.74 Cth 8.68 8.10 Clt 0.459 0.315 Clt (Av) 0.459 0.315 W(g) 254.10 277.10 293.23 W 254.10 23.00 16.13 Cw 9.05 5.82 — QCW 7.43 L = Back calculated length in cm h = Annual increment in cm Qh = Index of species average size Cl = Specific rate of linear growth Cth = Growth characteristic Clt = Growth constant Clt (Av) = Average growth constant W (g) = Calculated weight of fish w = Annual increase in weight in g CW = Specific rate of weight increase QCW = Index of population weight growth intensity parameter for demarcating the growth periods. In the present study, the values of (Cth) showed notable decline after the 2nd year. These growth trends clearly indicated that there was regularity in growth from 1st to 2nd year. This is in confirmation to the earlier studies on Labeo rohita (Johal Fish length (cm) and Tandon, 1985). The results also indicated an average annual length increment (Qh) of 15.93 cm and weight increment (QCW) Fig. 2. Harvestable size of Cirrhinus mrigala from Jawahar of 6.98 g (Table 3). It is interesting to note that, Johal and Sagar Dam, assigned on the basis of scale studies Tandon (1985), while studying growth parameters of L. rohita from three waters of northern India, observed Qh length of 66 cm is attained after the 2nd year as evident to vary between 10.67 and 11.19 cm. The average length from the back calculation of lengths (Table 2 and Fig. 2). increment (Qh) calculated in the present study is fairly By random autopsy of fishes caught, gravid female comparable despite being higher (15.93 cm) than the above specimens were observed in 2+ age group in the length stated Qh for other waters of north India. range of 28.5-61.20 cm. In some states of northern India, there is a legal limit Johal and Tondon (1987) also recommended prohibiting the harvest of fish of total length less than harvesting in the second and third year of life, when 30 cm by commercial fishing operations (Jhingran, 1982). the fish definitely attains a size above 30 cm in total length. A notable contribution for calculating the harvestable size However, in view of the varied ecological conditions of of Indian major carps namely Labeo rohita, catla different water bodies, it is difficult to make a generalization and C. mrigala from three reservoirs of northern India was for harvestable size and therefore the harvestable size made by Johal and Tandon (1987) who computed minimum calculated for C. mrigala from Jawahar Sagar Dam seems harvestable size range as 44.90-50.78 cm for L. rohita. to be appropriately useful for having sustainable fisheries Based on the present scale studies and back calculation of this important species. N. Sarang et al. 218

In view of the above, it can be inferred that C. mrigala Johal, M. S. and Tandon, K. K. 1985. Use of growth parameters enjoys a favorable environment in Jawahar Sagar Dam, in Labeo rohita (Pisces: ). Spolec Zoological., which offers opportunities for high growth of this species. 69: 101-107. Based on the above findings, it is felt that there is a need to Johal, M. S. and Tandon, K. K. 1987. Age and growth of Cirrhinus monitor the age and growth parameters regularly together mrigala (Pisces: Cyprinidae). Spolec Zoological., 51: with studies on fish population structure in a more 252-280. comprehensive manner. Kamal, M. Y. 1969. Studies on the age and growth of Cirrhinus Acknowledgements mrigala (Ham.) from commercial catches at Allahabad. Proc. Nat. Acad. Sci., India, 35B: 72-92. The authors are thankful to the Dean, College of Fisheries, MPUAT, Udaipur for providing necessary Khan, H. A. and Jhingran, V. G. 1975. Synopsis of biological data on the Rohu, Labeo rohita (Hamilton, 1822). FAO Fish facilities and encouragement for the research work. They Synopsis, p. 72. are also thankful to Dr. P. C. Verma, OIC, Environmental Survey Laboratory (BARC), RAPS, Kota, for providing Le Cren, E. D. 1951. The length-weight relationship, seasonal the laboratory facilities. cycle in gonad weight and condition in perch (Perna fluviatilis). J. Anim. Ecol., 20: 201-219. References Menon, M. D. 1953. The determination of age and growth of fishes Balon, E. K. 1968. The periodicity and relative indexes of the of tropical and subtropical waters. J. Bombay Nat. Hist. Soc., growth of fishes (with notes on their terminology). Mime 51: 623-635. International Conferences of aging and growth of fishes, Catla Smolenice, Czechoslovakia, p. 115-143. Natarajan, A. V. and Jhingran, V. G. 1963. On the biology of catla (Ham.) from the river Yamuna. Proc. Nat. Inst. Sci., Rao, H. L. 1974. Studies on the biology of Cirrhinus mrigala India, 29B: 326-355. (Ham.) of the river Godavari. Indian J. Fish., 21: 303-322. Pathani, S. S. 1981. Age and growth of mahseer, Tor putiora Jhingran, V. G. 1982. Fish and fisheries of India. Hindustan (Ham.) as determined by the scales and operculum. Matsya, Publishing Corporation, New Delhi, 666 pp. 7: 41-46.

Date of Receipt : 29/06/07 Date of Acceptance : 13/05/09